The husband and wife charged in a $7 billion Bank of New York money-laundering scandal may be offered a place in the federal witness protection program in exchange for testimony against their co-conspirators, sources said.

Lucy Edwards, a former bank official, and her husband, Peter Berlin, were taken into Federal Bureau of Investigation custody yesterday and are slated to plead guilty this morning to Judge Shirley Kram in Manhattan federal court, according to a spokesman for the U.S. Attorney.

They will admit to conspiring to launder money, sources said, and will also begin naming other Bank of New York employees and outsiders who assisted in the criminal fraud in exchange for a reduced charge and sentence, after months of negotiations with U.S. authorities.

Authorities are pressing to learn the role played by Natasha Gurfinkel Kavalovsky, the former Bank of New York executive who supervised Edwards. Kavalovsky, who resigned from the bank last fall, has not been charged with any wrongdoing, and her lawyer maintains that she never took any action that was in violation of the law.

Another former Bank of New York employee has been indicted in connection with the scandal. Svetlana Kudryavtsev was charged with making false statements to authorities investigating the money-laundering incident. She is also charged with having received about $30,000 from Edwards and Berlin.

The guilty plea from Edwards and Berlin is expected to be the first step to hearing the true role that Kavalovsky and Kudryavtsev played in the scandal.

But the offer of FBI protection suggests Edwards and her husband could face repercussions from the Russian mafia if they cooperate with authorities, sources said. While money laundering is often connected to mob activities, it was not known previously whether the Bank of New York incident had any ties to the mafia. A spokesman for Bank of New York declined comment, citing the ongoing investigation.

Authorities say Berlin’s company, Benex International, transferred huge sums from Russia through a number of accounts at the bank, where his wife was a high-ranking executive.

Edwards and Berlin were indicted last year on lesser charges of transferring money without a license. Tougher conspiracy charges suggest the feds are homing in on other suspects and the source of the money.

The couple’s lawyer, Barry Kingham, did not return calls for comment.

Bank of New York, which has been cooperating with the investigation, was unscathed by the new development in this long-running scandal. Its stock rose $1.13 to $36.94 yesterday.